In recent years a great deal of interest has been shown in the provision of a means to enable unmuffled voice communication from a protective firefighters mask and the like.
Some illustrative examples are shown in the patents noted below.
U.S. Pat. No. 4,508,936 issued Apr. 2, 1985 to Robert Ingall, shows and describes a communication system that utilizes an amplifier/speaker unit (32) that is mounted on the firefighter's waist-belt and is connected to the face mask via a cable (30). The system appears to use an induction method of transmission which is relatively sumptuous of battery energy and can either cause interference with and/or receive interference from external transmission signals. Another problem with this device is the high possibility of getting the cable (30) caught on something like a nail or other projecting object resulting in possible loss of communication and/or dislodging the face mask of the wearer while in a hazardous air (fire) environment.
U.S. Pat. No. 3,180,333 issued Apr. 27, 1965 to R. D. Lewis appears to show and describe a gas mask device that uses a signal transmitting line (50) mounted to the belt of the wearer. The amplifier unit is molded into/for a specific mask and therefore has limited use, which increases its relative repair/replacement costs. The amplifier and microphone appear to be hard wired through the mask by an adaptor which therefore results in a breach of the mask wall. The breach may result in a loss of integrity of the mask. This device also has the inherent problems noted above with regard to the Ingall's patent.
Other prior art patents of interest include U.S. Pat. No. 3,314,424 issued Nov. 14, 1962 to M. Berman; U.S. Pat. No. 2,953,129 issued Sept. 20, 1960 to A. Bloom et al; U.S. Pat. No. 2,997,550 issued Aug. 22, 1961 to A. D. Traller; U.S. Pat. No. 3,540,442 issued Nov. 17, 1970 to Robert L. Holloway; and U.S. Pat. No. 2,950,360 issued Aug. 23, 1960 to R. K. Duncan.
These patents are mentioned as being representative of the prior art and other pertinent references may exist. None of the above cited patents are deemed to affect the patentability of the present claimed invention.
The present invention involves a novel combination of features and components combined in such a way as to afford a very efficient, cost effective, relatively more reliable, easier to use solution to the difficulties and problems encountered with the prior art.
The present invention resides in part on the use of infra-red signal coupling between the microphone and the speaker-amplifier, through the face plate of a standard mask. The mounting of the microphone unit on the inside of the mask and the speaker-amplifier on the outside of the mask without breaching the mask's seals, face plate or other constituent components. The obviating of any need for connecting cables. The ease and inter-changability of the microphone and the speaker-amplifier for quick and simple repair. The ease of replacing batteries. The relative ease of use obviating the need for connecting cables and mounting speakers to belts and the like.